From publisher blurb:
Characters to Bend Reality and Crush their Enemies
Do your PCs need to hire an extra sword arm with some arcane talent to boot? Does your upcoming session need an evil wizard that can go several rounds in a melee fight? Are you seeking ideas for the terrible power at the end of your campaign? The Book of Beasts: Magus Codex has the solutions you need, arming Game Masters of the First Edition of the Pathfinder Roleplaying Game with the following:
20 ready-made magus characters, one for each level of play
Tactical combat recommendations for every character, helping you to quickly and effectively run the NPC in a fight
Personalities and details to give you ideas on how to use the characters both in combat and in roleplaying interactions